making pinhole aperture for SLR

Discussion in 'Pinhole Photography' started by freedda, Jan 2, 2005.

  1. freedda

    freedda Member

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    I'm very new to pinhole photography. I'm trying to mounted a pinhole aperture opening on a body cap for my SLR by drilling a hole with a sewing needle into a thin brass shim (as described in Jim Shull's intro pinhole book).

    I've been able to get images with objects in focus up to about 20 feet away; beyond that they get blurry. I'm not sure if I need a larger pinhole, smaller pinhole, or a hole that is drilled "cleaner." Shull's book claims I can get a clean pinhole opening with this method, but I'm not sure its working. Any suggestions?

    Regards, David.
     
  2. Ed Sukach

    Ed Sukach Member

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    There is a web site that should be very helpful:

    [ http://www.mrpinhole.com/holesize.php ]

    Offhand, I'd guess that the pinhole diameter for a 35mm body cap would be **small**. LOTS of other good information - exposure, etc., as well.

    BTW: Welcome to APUG!!
     
  3. Lee L

    Lee L Member

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    I've tried a few shots with a pinhole in a rangefinder body cap. My pinhole was from a set in stainless steel by Eric Renner at pinholeresource.com, sized 0.0087 inches, where the web site mentioned above recommends 0.009 inches for the focal length of my setup, which is 28mm. This works out to about f:130.

    I don't have a lot of shots with this, but you can see one (without much in the distance) at:

    http://www.oberlin.edu/observatory/DomePinhole.jpg

    The pinhole/camera is at:

    http://www.oberlin.net/~lee/BessaPinhole.jpg

    You can see that I blacked out the pinhole with a Sharpie permanent marker to cut down on reflections and flare. Hope this helps as an example of what to expect.

    With an SLR, and its longer film-to-lens-flange distance, you'll want to use a different sized pinhole, as the diffraction limit that determines optimum pinhole size will allow you to use a somewhat smaller f:stop, perhaps in the f:150 to f:200 range. There are some lists on the web that have film-to-lens-flange distances that you can plug into the mrpinhole calculator, but I couldn't find a really comprehensive one in a quick search.

    Hope this helps.

    Lee
     
  4. mdohoney

    mdohoney Member

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    Check out the f295 website. Lots of helpful folks and wonderful photos. My experience with pinhole is that everything that there's enough light to see is equally in/out of focus. I use a pinhole in a body cap with (shh, don't tell) a digital SLR, a converted Brownie box, a foamcore box with a Polaroid back or 4X5 back with paper, and the odd cookie tin/oatmeal box. If you're making your own pinholes I suggest you not mount them permanently, so that you can try to vary the size. Keep trying, it's fascinating- an empty space with a hole in it!
     
  5. mdohoney

    mdohoney Member

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    Oh, and also World Wide Pinhole Photography day is coming up, the 3rd Sunday in April, I think, when pinholers everywhere go out to make pictures and post them to one site. There's a link at f295, and a gallery from last year.
     
  6. mdohoney

    mdohoney Member

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    Good! You've found it!